Hydraulic actuating mechanism for dump trucks



H. '0. DAY

Sept 14, 1948.

HYDRAULIC ACTUATING MECHANISM FOR DUMP TRUCKS Filed Nov. a, 1946 3Sheets-Sheet 1 INVENTOR:

Herbert 0. Day

PLO DAY Sept. 14, 1948.

HYDRAULIC ACTUATI NG MECHANISM FOR DUMP TRUCKS Filed Nov. 8, 1945 3Sheets-Sheet 2 INKENTOR: Herbefl 0. Day

mm 9% mm mm -t. 14, 1948. H. 0. DAY 9,

HYDRAULIC ACTUATING MECHANISM FO R DUMP TRUCKS Filed Nov. e. 1946. v sSheets-Sheet s I 20. VMVVENTOR: l8 Herbert O.-D y

Patented Sept. 14, 1948 HYDRAULIC DUMP moons Herbert i0- Day,Bowling-Green, Ohio ApplieationNoveniber 8, 1946, SerieiNo. 1138;332

This invention relates to loaddumping mechanisini in 'vehicles 1 andmore specifically to actu ating mechanism for the tiltable vehicle bodyof motor trucks; Fdrtherparticularized this relates to an improvedarrangement-of hydraulic act'u ating cyli nders in such 'actuatingmechanism in WhiclT tfie hydiaulie power is fiirn ished by ahydraulimpumpwhich'is driven fromthe truck engine;

Ohe oi theroblemsin the construction of such aetuating mechanism is toprovide effective and-favorable force leverages or moments,- on toderlvefront the pcomer"cylinders a maximum force component for thetilting of the loaded=truck= may-mmmns-mnmr horizontal position. Thatposition is-diffieult for the lifting forces to apply since the spaceavailable for such mechanismunderneath the truck body and between it andthe chassis'is crowded:

Other problems lie in' the contradictory re quirements that a maximum oflehgth'of movement of: the truck bodyshould be attained with a;relative: minimum of cylinder length, of piston l rod len'gtht and'ofpiston "travelj Another prob lem is how to minimize mechanism stressesupon the fome-sustaining' parts and operating members'i Structural l andiun'ctional problems to he Y met in the oonstruction of such' mechanismmay. be said: 130? reside in: obtainin iavorable force leverages in acompact space; minimizing =tl'ie extent' of :piston' rod length in view''oi guidaneesrequired l for and:- conmpression stresses imposed: uponthe pistm r rod of the hydraulic cylinder;minimizing; cylinder diameterand; tcyl'ind'e'r wait thioknesses whilmdleit'm'mg maximumeffectivewlittirrg forties, redneingamechanical stresses open the mechanismvand-"associated parts as wen- "as "reducingtheirwweighthreducingthe peakl torque onpeekv power req irementssorpeakhydraulic pressures required; for lifitingythe load of: thetruck'bodsand towderivevimm thefoperation'of the mecha niem load-lifting effectsomitting: moments which" vary a desired. manner with the angulawposietion-of the .tiltin ztrnckxbody.

1i; iseamong thewobjectswof thisinvention to pmvidewhydnaulically-"joperated actuating; mecha-w ni'sm capable of: meeting one: on more ofthe tone i going problems. i

To this end I provide an arrangement ofihydraulic EI'pOWBI'. cylindei sin which the. resultant poir itv of force application variesautomatically inxadesired manner during,- theitilti-ngimovementv oflthebody-i structumltvaspeaking llzp zovidea pluwlity oi ings there hasbeen illustrated: the;

According to one feature I proizide a frifiifiji inden and hehindi itendiixilia'iifv" cylinder, bo "'th inclined tow'ti dsl the tilting axisf-the body; the: main eylinderrbeine closer'to'tne tilting axis 1lifting: forces are applied at successive-points along:"the'vtruok bodwlAt the bee-inningtune-1 body' tiltine movement both cylinders applifthircombined: fitting 'hovl'feito the body" as the amid-1:

iamrpis-ton rod eiitends fasteithan the main pie:

toi'i' rodi At an inti 'fiiediate poititofi the tilting' movement;namely: at? the K endofl travel of the auxiliary-piston rod,ctlia3t rodfunctionally de taohesfi'tself from -tiie truck body we linkube tween itrendithe body becomes effectiveto mam:

tam"-resvpredeterminecl relettiofiship between them; thus leaving it "tothe fliairi' 'eyli'rider alone to corn: plete 'tkieT-til'titig movementof the body' for the purposezof dmhiingizthe loeid.

cylinders-e one at :eacn'side 'ofithech-assis and at single: auxiliarycylinder centrally 'di'siiose'd/ be hind-them." l l i It isiiariron gs.the advantages: of'athi-st in vention thett becanse ofi a the" addition"of the auxiliary. S'llfipdffidfilliVfl -fr'om theeuxil'iary cylinder,the: lengtln of the tree overhanging portion; of *the truckl body; isshortened; with-athei -result thatxth'e bending stresses *upon thetm'ckfloodyore' relative 1y; diminished :so that a, lighter body 9'structure mamsum'oe. l l i I The invention" possesses-other objects; and{feaa turee -oi 1adv!amtage;i some of which with? the fore going'ijiwiil be'rseti forth irr lthevf-ol'lowing" de'sorip'f-v tioni" L I-nwtheifollowing description and isrrthew claims, parts will be identified byspecific' naahes for conveniencew but they arelintefidd to be tatsgeneric? in wtheir application to similair p'ttrtz ast the: artrw i'llriperm-it In the? acoomfiamt'mg: dm'w best rem'bddi ment of the inventionknown to me, but such embodiment is to be regarded as typical only ofmany possible embodiments, and the invention is not to be limitedthereto.

The novel features considered characteristic of my invention are setforth with particularity in the appended claims. The invention itself,however, both as to its organization and its method of operation,together with additional objects and advantages thereof, will best beunderstood from the followin description of a specific embodiment whenread in connection with the accompanying drawings in which Fig. 1illustrates the trailer hitched to a truck;

Fig. 2 is a plan view of the trailer with parts broken away to disclosethe lifting mechanism;

Figs. 3, 5, 6 and '7 illustrate the function and coaction of thehydraulic cylinders, that isthe action of the main cylinders with theauxiliary or booster cylinder, in a sequence of tilting phases orangular positions of the body;

Fig. 3 shows the starting phase when the body is in its initialhorizontal position with all piston rods of the cylinder fullyretracted;

Fig. 4: is a plan view of Fig. 3 with a bottom poI-- tion of the boxbody broken away to disclose the power cylinder arrangement underneath;

Fig. 5 shows the main and auxiliary piston rods partially extended andthe box body in a slightly raised position; 1

Fig. 6 shows the auxiliary piston rod fully extended, the main pistonrodin a corresponding partially extended condition, and the box body ina correspondingly higher raised although still intermediate position; 1

Fig. 7 shows the main as Wellas the auxiliary piston rod fully extendedalthough with the aux iliary piston rod operatively detached from thebox body and the box body thus fully raised.

In order to raise the body ID from its Fig, 3 lower or rest positionhydraulic pressure-fluid is admitted to the-bottoms of all cylinders,that is the main as well as the auxiliary cylinders, forcing all pistonrods to extend and to co-act in raising the body from its'initialhorizontal position. During this initial lifting phase as indicated bythe angle a in Fig, 5 the force exerted by the piston rod 54 of theauxiliary or booster cylinder is being applied at a point of the bodymore favorable than the forces exerted by the piston rods of the maincylinders 32 and 33, even though all co -act in exertin a combinedpowerful initial lifting moment upon the body. When the auxiliar -piston,rod 54 will have fully extended to its Fig. 6 positionthe body willhave reached a steeper tilting angle b whileth'e piston rods of the maincylinders 32 and 33 will have reached an intermediate point of extensionat which the forces exerted by them act upon the body undera morefavorable load lifting angle than they did in their initial (Fig. 3)position. -As the outward movement or extension of the two main pistonrods continues as a result of continued hydraulic pressure, theauxiliary piston rod 54 having reached its terminal (Fig. 6) positionwill functionally. detach itself from the body 10 when subsequently (seeFig. 7) the link member 59 becomes effective in allowing the main pistonrods alone to complete the tilting or dumping movement or" the body.

The end tiltin position of the body is indicated inFig. 7 showing thepistons of all cylinders as having reached the outer end of theirtravel, and the body being tilted at an angle 0.

invention as embodied in a swingable or tiltable about The invention isherein shown to be embodied in trailer [0 hitched to a truck llindicated by a chassis frame l2 on wheels l3 and I4, and a drivers cabl5.

The trailer I0 comprises a frame IS the rear end of which is supportedby wheels I! and 18 while the front end is supported upon the chassisframe of the truck by means of a turntable construction H) in "acustomary manner. Upon the frame It is mounted a load-receiving box body20 a horizontal axis at the rear end of the frame, namely about a shaftor pivot 2L: The frame is indicated by longitudinal beams or stringersZ2 and 22 and 22 and 22 and transverse members 23 and another kind oftransverse members 23, 23 and 23. The box body is shown to comprisesides 24, ends 25 and anism comprising 26, and a bottom 2'! (see Fig.4).

The bodyand load-lifting mechanism is attached to the under side of theframe It and comprises a pair of parallel side plates or shields28 and29 having their upper horizontal edge portions-fastened to respectivestringers 2 2 and 22';

as by bolts 39 and their lower ends rigidly inter connected as by atransverse beam 3!.

Between the shields 28 and Z9 and carried thereby are a pair of mainhydraulic power'cyl lnde-rs 32 and their bottom ends 32 respectivelybeing mounted upon a shaft 34.0811- ried by and extending between theshields 28 and 29, so that the cylinders areswingable about a horizontalaxis. The cylinder 32 has a piston 35 a piston rod 36 the outer end 31of which lodges between ribs 38 and 39 of a bracket memher 49 and ispivotally connected thereto as at M.

The other main cylinder33 has a piston 42 and a piston rod 43 the outerend 44 of which lodges between ribs 45 and 46 also constituting part ofthe bracket member which in turn is disposed between and fastened to thetransverse members 23 and 23 of the body Hi. I

A single auxiliary is disposed centrally with respect to the two maincylinders although spaced therefrom a-distance 11 towards the front endof the trailer.

The cylinder 41 is also swingably mounted since bottom end is unitarywith a transverse shaftits 48 the .ends of which are iournalled as3.12.49 and 56 upon the respective vertical shields 28 and-29. A pair ofsymmetrically disposed reinforcing ribs or stiffeners cylinder at eachrespective side thereof and rigidly connect a portionof a swingable orlink member 59 comprising a pair of symmetrically disposed arms [itand'tl rigidly interconnected at one end by thetransversemember 58 andat the opposite end by a transverse shaft 62 journalled as at53 upon theunder side of the transverse'member 23.

Each of thearms '60 and 6| has a longitudinal end portion 64, adiagonally extending portion 65,

and a longitudinal portion '66.

Iclaim: 1. Load-dumping mechanism for a vehiclehaving' a'chassis frame,and a'truck body til'table upon said chassis about a horizontal axisextending transversely of the chassis frame, said mech-' a mainhydraulic power cylinand 33 hydraulic power cylinder 47;

5| and 52 extend the length of thethe cylinder with the shaft 48 in a'manner more clearly shown in my co-pending has a piston 53 and pivotallyconnected The ribs 56 and'57 constitute partof which in turnconstitutes,

der the rear end of which is mounted upon said chassis frame to swingabout a horizontal axis representing the pivotal point of the cylinderand which has a piston rod engaging the truck body, an auxiliarycylinder spaced from said main cylinder and having its rear endpivotally mounted upon said chassis frame at a point spaced farther fromsaid horizontal body-tilting axis than the pivotal point of said mainpower cylinder so as to swing about a horizontal axis parallel to saidother two horizontal axes and having an auxiliary piston rod engagingsaid truck body, and automatic means for operatively disengagin theauxiliary piston rod from the body when the body continues tilting pastthe maximum extension of the auxiliary piston rod, and for operativelyreconnecting said piston end with the body at a pre-determined point ofthe return movement thereof.

2. Load-dumping mechanism according to 20 claim 1, in which saidautomatic means comprise a link member connecting the end portion of theauxiliary piston rod with the truck body which member is disposed in theplane of movement of the auxiliary cylinder.

3. Load-dumping mechanism according to claim 1, in which one maincylinder is disposed REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,638,009 Cambessedes Aug. 9,1927 2,326,594 Wood Aug. 11), 1943

